Shed Parts Glossary And Terminology

Shed Structural Components:

Columns: Vertical structural members that support the roof and transfer loads to the foundation, typically C Sections or RHS

Rafters: Pitched beams that run from the apex to the eaves, creating the roof frame and supporting the purlins and roof sheeting. Angles typically range from 5% – 30%

Portal frames: A completely constructed frame consisting of columns and rafters connected at the knee and apex joints that form the central support system of a shed.

Purlins (roof): Horizontal structural members fixed to the rafters that support the roof sheeting that are typically Z Sections or Top Hats.

Girts (wall): Horizontal structural members that run along the outside of the columns, supporting the wall sheeting and strengthening the building that are made of bolted Z Sections or tek screwed Top Hats.

Eave purlins: Purlins are located at the eaves of the shed, providing a meeting point for both wall and roof sheeting. The top of the Eave purlin is generally considered the height of the building. 

Mullions are vertical columns in the gable end walls that share the load with girts to support the wall sheeting. They are also known as end-wall mullions. 

Door Headers are additional sections that run across the top of door or window openings, providing extra strength and a fixing point for header sheeting. These are generally used on roller doors and personal access doors.

Trusses: Structural components that support the roof, often used interchangeably with rafters in shed construction. Trusses are typically used on larger sheds with spans of over 25m.

Beams: Horizontal structural elements that support loads from other components and transfer them to columns or walls.

RHS: Rectangular Hollow Section, a steel profile used in shed construction. Generally used for columns and rafters.

C Sections: Steel purlins shaped like a “C” are commonly used as columns and rafters to form a portal frame. They typically range in size from 100mm to 400mm and vary in thickness from 1mm – 3.5mm.

Z Sections: Steel purlins shaped like a “Z”, often used as roof purlins and wall girts due to their ability to lap. They are also used as roller door jambs. They range in size from 100mm to 350 and in thicknesses from 1mm to 3.5mm.

Top Hats: High-strength and low-weight sections are used as roof purlins and wall girts to fix roofing and walling sheets, typically in domestic sheds and garages. They generally come in 3 sizes: 64mm, 96mm, and 120mm. They generally come in three thicknesses: .75mm, .95mm and 1.15mm. (Suppliers typically call these .75mm, 1mm & 120mm to round the thickness off)

Mezzanine joists: Horizontal structural members running from a bearer or girder to support a mezzanine floor within a shed, typically made from C Sections or Z Sections.

 

Shed Cladding and Roofing:

Wall sheeting: Metal sheet panels that cover the exterior walls of the shed, providing protection from weather and enhancing the structure’s appearance. All sheds supplied by True Blue Sheds use Bluescope’s Colorbond or Zincalume.

Roof sheeting: Metal sheet panels that are installed on the roof to protect the shed from rain, sun, and other weather conditions. We only use Colorbond and Zincalume for our cladding. 

Colorbond cladding: An Australian brand of pre-painted steel cladding known for its durability, corrosion resistance, and wide range of over 22 colour options. 

Zincalume cladding: A steel cladding with a zinc and aluminium alloy coating that offers excellent corrosion resistance and a distinctive metallic appearance. Made in Australia by BlueScope.

Trim cladding: This deep pan, 5-ribbed high-profile steel cladding is suitable for both walls and roofs and is known for its strength and aesthetic appearance. 

Corrugated Cladding (Custom-orb): This traditional corrugated profile offers a classic look and is suitable for both roof and wall applications.

BMT: The thickness of the metal sheeting before any coatings or paint are applied. Sheds typically use Colorbond or Zincalume with a BMT (Base Metal Thickness) of .42mm and .48mm.

TCT: The overall thickness of the metal sheet after coatings and paint have been applied, including the base metal thickness. BlueScopes Colorbond and Zincalume have TCT (Total Coat Thickness) of .47mm and .53mm.

Wainscot: The lower portion of the walls is covered with a different cladding colour, and the Wainscot’s height can be varied. 

 

Shed Doors and Windows:

Roller doors: Metal doors that roll up vertically into a coil above the door opening. They are space-efficient and provide a wide opening for easy access, which is particularly useful for storing large items or vehicles. These usually come in Series A (up to 3m high x 3m wide), Series AA (up to 3m high x 5.4m wide) and Series B doors (over 3m high and up to 5.4m wide)

Metal Sliding doors: Doors that move horizontally along a top or bottom track, typically consisting of one or more metal panels.

Personal Access (PA) doors: These are standard-sized doors designed for quick and easy human entry and exit. They are typically made of RHS frames and clad in Colorbond. They function similarly to regular house doors. The standard size used in the shed has a width of 820mm.

Glass Sliding Doors: These are sliding doors featuring glass panels, allowing natural light into the shed while providing access.

Shed Windows: Openings in the shed walls that allow natural light and ventilation. They come in various styles and sizes and are usually made from powder-coated aluminium in a Colorbond colour.

Frame Only opening: A structural framework for doors or windows without the actual door or window installed. It allows clients to supply their own windows or doors.

Wind locked Roller Doors: Specialized roller doors designed for high wind areas, particularly in cyclonic regions. These doors have additional locking mechanisms to withstand strong winds. These doors are required to be used in Cyclonic areas in Australia under the NCC2022 but are recommended for all high-wind speed locations.

 

Shed Rainwater Management:

Gutters: Metal channel installed along the eaves of the shed roof to collect and divert rainwater. They come in different sizes and styles, but sheds typically use a quad or square gutter, which can be slotted or unslotted. 

Downpipes: Pipes that carry rainwater from the gutters to the ground or a drainage system. They are typically made of rectangular Colorbond or Zincalume material. PVC piping is also commonly used for direct connection to rainwater tanks.

Gutter brackets: Gutter brackets are support structures that attach gutters to the shed’s wall sheeting or eve, ensuring the gutter can be angled correctly for water collection and drainage.

 

Shed Flashings and Seals:

Ridge capping: A protective metal sheet that runs along the peak of the shed roof, covering the joint where two roof sheets meet at the apex. It prevents water infiltration and enhances the roof’s appearance.

Barge capping: A metal flashing installed along the gable or skillion ends of the roof, covering the edge where the roof meets the wall. It protects against water ingress and provides a finished look to the roof edge.

Corner flashings: Folded Metal flashing that is used to seal and protect the joints at the corners of the shed structure. They prevent water penetration and improve the overall look of the building. 

Vermin seal / Vermaseal: A specialized product that prevents pests from entering the shed where the sheeting meets the slab. A slab rebate under the bottom of the wall sheeting can also used to stop pests.

Header Flashings: Folder metal flashings are installed above door and window openings to direct water away from these vulnerable areas and prevent water ingress.

 

Insulation:

Shed Roof Insulation: Insulating a shed roof helps maintain a consistent temperature inside the shed and protects against heat loss, it can also help run off any condensation that forms under the roof sheeting. 

Shed Wall insulation: Insulating shed walls helps create a more comfortable environment and protects stored items from temperature fluctuations.

 

Bracing:

Cross bracing: Steel straps or threaded rods installed diagonally between structural members to provide stability and resist lateral forces, particularly in larger sheds or high-wind areas.

Strap bracing: A type of bracing that uses metal straps installed diagonally to provide strength and stability and prevent movement in the shed structure.

Knee Bracing: Additional support is installed at the top corner of a shed at the connection point between columns and rafters, enhancing the shed’s structural integrity. These typically are made of C Sections.

Apex Bracing: Apex bracing, made of C sections, adds additional reinforcement at the roof’s apex (highest point) where the rafters meet.

Fly Bracing: A brace that runs from the girt or purlin around the rafter or column, providing lateral restraint to the rafter or column.

Rod Bracing: Similar to strap bracing, metal rods instead of straps are used to provide structural stability.

Diaphragm bracing: The roof and wall sheeting provide a bracing effect, which helps stabilise the overall structure.

Bridging: Additional support members are installed between columns or rafters to increase stability and reduce flexing. These are typically 22m or 40mm roofing battens, but they can sometimes be top hats.

Rake Angle: A trim angle is installed on the apex of the end walls to attach the top of the wall sheeting. These are typically come in a 50×50 folded L-shape

Corner Angle: A trim angle installed on the corners of a shed from the eve to the bottom girt to allow the fixing of the wall sheeting. These are generally folded into a 50×50 L shape.9

 

Shed Bracketry

Apex brackets: Folded metal brackets that are used to join rafters at the highest point of the roof, ensuring stability and proper load distribution at the apex.

Haunch brackets: Also known as knee brackets, connect columns to rafters at the eave, providing support and strength to the frame.

Hold-down brackets: These brackets secure the shed’s columns to the concrete slab or foundation, anchoring the structure and preventing uplift in high winds. These brackets vary but are typically cast in the slab or bolted-down U or L brackets.

Cleats: Various shaped metal L-shaped connectors are used to join different sections of the shed together, typically fastened with nuts and bolts or tek screws.

 

Additional Components:

Skylights: Transparent panels made from fibreglass or polycarbonate are installed in the roof to allow natural light into the shed, reducing the need for artificial lighting during daylight hours.

Mezzanine floors: An additional elevated floor level within the shed, typically used for storage or to create extra usable space without increasing the building’s footprint. They can also be used to separate the roof are and create a flat roof under them. 

Vented ridges: Openings along the peak of the roof that allows for air circulation, helping to regulate temperature and reduce moisture buildup inside the shed.

Roof wire (Safety Wire): Wire installed under skylights to provide fall protection, ensuring safety during roof installation and maintenance. This wire is also commonly used under builders’ wrap on the ceiling of sheds when trying to stop condensation. 

Whirlybird: A wind-driven ventilation device installed on the roof of a building to improve air circulation and reduce heat buildup in the shed.

 

Shed Design Elements

Gable Roof: A triangular roof style, also known as a pitched roof. The angle of the gable roof can be varied to change the look and typically comes in 5,10,15,20,22.5,25,27.5, and 30-degree roof pitch options.

Skillion Roof: A single-sloped roof structure, also known as a lean-to, which slants in one direction; these generally come in 5,10 and 15-degree roof pitches.

Hip Roof: A hip roof typically has slopes on all four sides that come together at the top. This roof style is used more on carports than sheds.

Dutch Gable Roof: A combination of a gable and hip roof, featuring a small gable at the top of a hip roof, the roof design is used on carports more than sheds.

Shed Eves: The roof continues past the shed wall to produce an overhang of the roof, typically used as protection from the rain.

Eve Height: The vertical measurement from the top of the slab to the top of the eve purlin. This is generally referred to as the shed height.

Apex Height: The height of the highest point of the shed roof where the two rafters meet.

Roof Pitch: The angle or slope of the roof from the apex to the gutter; these angles are typically 5, 10, 15, 20, 22.5, 25, 27.5, and 30 degrees.

Bays: The distance between portal frames or primary support columns. Bay spacings can be uniform or each bay can vary as required.

Awnings: Extensions of the roof, usually on the side or front of the shed, provide additional shelter. They can be fully open, fully closed, or a combination of the two.

Lean-to: Another term for an awning roof, a single-sloped structure often attached to the main shed

Slab: The concrete base on which the shed is constructed

Shed Snow Loading: The design consideration for the weight of snow on the roof is particularly important in areas with heavy snowfall.

Concrete Piers: Aholes are drilled into the earth and filled with concrete to support portal frame elements. They can be installed as part of a slab or standalone. Sometimes, the main portion of the shed is installed on piers and a slab combination, while the awning is supported by concrete piers only.

Slab Thickness: The depth of the concrete slab, this varies depending on the shed’s size and intended use. Typical shed engineering supplied covers 100mm, 125mm and 150mm.

Footing Depth: The distance the concrete pier extends below ground level and then filled with concrete.

Footing Diameter: The width of the concrete pier that needs to be drilled and filled with concrete. 

Moment Frame: This is typically used to replace the need for strap bracing. It consists of a piece of C section that runs up one column, across the eve and back down the next column. 

Open Bay: A section of the shed that is open on one or more sides, often used for equipment access.

Internal wall: A wall within the shed that divides the interior space.

Frame only Sheds: Sheds supplied with only the structural framework, allowing for customization of cladding and other components.

BOM: A comprehensive list of all components and quantities needed to construct the shed.

Bluescope Steel: A major Australian steel manufacturer known for producing high-quality steel products such as Colorbond and Zincalume for shed construction.

Awning Drop: The vertical distance an awning extends down from its attachment point or the side of a shed.

Slab Rebate: A recessed edge around the perimeter of the concrete slab, often used for improved water resistance and vermin-proofing

Wind Speed is a crucial engineering element in shed design, measured in meters per second, and it determines the required building strength and steel specifications.

Side Wall: The walls along the length of the shed, usually featuring gutters, can be clad or unclad.

Shed Span: The width of the building, typically measured across the gable end and to the outside of the columns.

Clear Span: The unobstructed distance between support columns allows maximum usable space.

Terrain Category: A classification of the surrounding environment that affects shed design, such as open, semi-sheltered, or sheltered.

 

Shed Fasteners and Fixings:

Tek screws: Self-drilling, self-tapping screws with a hexagonal head used for various connections in shed construction. They come in different sizes and are used to attach cladding to purlins and girts. Those used on walling, roofing, and flashings typically have a neoprene washer for waterproofing.

Nuts and bolts: These are typically called framing bolts and can vary in thickness and length. They are used for connecting the major components of a shed, such as the haunch and apex brackets. They usually come in Zinc or Galvanized versions to prevent rust and corrosion.